The Beauty and Joy of Computing Lecture #1 Welcome; Abstraction Instructor : Sean Morris Watch the student testimonials about the course, what it means to them, and how it has changed their lives. Inspiring! inst.eecs.berkeley.edu/~cs10/

At a time when computing is the new literacy, what significant challenge does the US face in its effort to maintain a robust computing workforce? a)Underproduction – i.e., schools are not producing enough students to fill the projected number of job openings b)Underrepresentation – i.e., people choosing CS do not represent diversity of US c)Lack of presence in K-12 education – i.e., the number and quality of CS classes in high schools is abysmal d)All of the above e)None of the above

UC Berkeley “The Beauty and Joy of Computing” : Welcome, Abstraction (3) Garcia  Big Ideas of Programming  Abstraction  Algorithms (2)  Recursion (2)  Functions-as-data, λ  (2)  Programming Paradigms  Concurrency  Distributed Computing  Beauty and Joy  “CS Unplugged” activities  Lab work in pairs  Two projects in pairs  Of your own choice!!  One blog  Of students’ own choice!!  Big Ideas of Computing  HowStuffWorks  3D Graphics  Video Games  Computational Game Theory  Research Summaries  AI  HCI  Apps that Changed the World  Social Implications of Computing  Saving the World with Computing  How Twitter Works  Cloud Computing  Future of Computing BJC in one slide

UC Berkeley “The Beauty and Joy of Computing” : Welcome, Abstraction (4) Garcia  Format (12 hrs/wk * 8 wks)  Selected Reading  Taken from great book (“Blown to Bits” by Abelson, Ledeen & Lewis) + articles + videos  Current events EVERY DAY All resources FREE  Even clickers! Format & Textbooks … MonTueWedThu Lecture Lab Discussion

UC Berkeley “The Beauty and Joy of Computing” : Welcome, Abstraction (5) Garcia Week at a glance

UC Berkeley “The Beauty and Joy of Computing” : Welcome, Abstraction (6) Garcia Let’s check enrollments (in real time)  We have NEVER turned anyone away … if more students sign up, we’ll open up more sections!  I don’t intend to turn anyone away now

UC Berkeley “The Beauty and Joy of Computing” : Welcome, Abstraction (7) Garcia Peer Instruction  Increase real-time learning in lecture, test understanding of concepts vs. details  1-2 minutes to decide yourself  2 minutes in pairs/triples to reach consensus. Teach others!  2 minute discussion of answers, questions, clarifications

UC Berkeley “The Beauty and Joy of Computing” : Welcome, Abstraction (8) Garcia Piazza for {ask,answer}ing questions

UC Berkeley “The Beauty and Joy of Computing” : Welcome, Abstraction (9) Garcia  EPA  Rewards good behavior  Effort  E.g., Office hours, doing every single lab, hw, reading Piazza pages  Participation  E.g., Raising hand in lec or discussion, asking questions on Piazza  Altruism  E.g., helping other students in lab, answering questions on Piazza  You have 3 “Slip Days”  You use them to extend due date, 1 slip day for 1 day extension  You can use them one at a time or all at once or in any combination  They follow you around when you pair up (you are counted individually)  E.g., A has 2, B has 0. Project is late by 1 day. A uses 1, B is 1 day late  Late is 1/3 off/day Pro-student Grading Policies

UC Berkeley “The Beauty and Joy of Computing” : Welcome, Abstraction (10) Garcia  Detail removal  “The act or process of leaving out of consideration one or more properties of a complex object so as to attend to others.”  Generalization  “The process of formulating general concepts by abstracting common properties of instances” Abstraction Henri Matisse “Naked Blue IV”

UC Berkeley “The Beauty and Joy of Computing” : Welcome, Abstraction (11) Garcia Detail Removal Automatic Generation of Detail Maps Maneesh Agrawala (UCB EECS), among others

UC Berkeley “The Beauty and Joy of Computing” : Welcome, Abstraction (12) Garcia  You’ll want to write a project to simulate a real- world situation, or play a game, or …  Abstraction is the idea that you focus on the essence, the cleanest way to map the messy real world to one you can build  Experts are often brought in to know what to remove and what to keep! Detail Removal (in BJC) The London Underground 1928 Map & the 1933 map by Harry Beck.

UC Berkeley “The Beauty and Joy of Computing” : Welcome, Abstraction (13) Garcia From what you have learned so far, which of the following is NOT a great example of abstraction?  Google’s search results page  How a master surgeon would teach an apprentice a particular technique.  An elevator pitch for a screenplay  The next football play radioed in by the coach to the quarterback. Consider this…

UC Berkeley “The Beauty and Joy of Computing” : Welcome, Abstraction (14) Garcia  You have a farm with many animal kinds.  Different food for each  You have directions that say  To feed dog, put dog food in dog dish  To feed chicken, put chicken food in chicken dish  To feed rabbit, put rabbit food in rabbit dish  Etc…  How could you do better?  To feed, put food in dish Generalization Example

UC Berkeley “The Beauty and Joy of Computing” : Welcome, Abstraction (15) Garcia  You are going to learn to write functions, like in math class: y = sin(x)  You should think about what inputs make sense to use so you don’t have to duplicate code Generalization (in BJC) “Function machine” from Simply Scheme (Harvey)

UC Berkeley “The Beauty and Joy of Computing” : Welcome, Abstraction (16) Garcia Abstraction is also seen when creating contracts, or specifications between entities. For example, say you are going to hire a contractor to dig a ditch. If you followed proper rules of abstraction, what would you be able to specify to the contractor?  Who on their team should dig the ditch.  Where to dig the ditch.  How to dig the ditch.  All of the above.  None of the above. Consider this…

UC Berkeley “The Beauty and Joy of Computing” : Welcome, Abstraction (17) Garcia  How many of you know how a car works?  How many can drive a car?  Abstraction! Think about driving a car We only need to worry about the interface, or specification, or contract NOT how (or by whom) it’s built bove the abstraction line Someone who died in 1930 could still drive a car today because they’ve kept the same Abstraction! (right pedal faster, left pedal slow)

UC Berkeley “The Beauty and Joy of Computing” : Welcome, Abstraction (18) Garcia  Examples:  Functions (e.g., sin x)  Hiring contractors  Application Programming Interfaces (APIs)  Technology (e.g., cars)  Amazing things are built when these layer  And the abstraction layers are getting deeper by the day! The Power of Abstraction, everywhere! Abstraction Barrier (Interface) (the interface, or specification, or contract) Below the abstraction line This is where / how / when / by whom it is actually built, which is done according to the interface, specification, or contract. We only need to worry about the interface, or specification, or contract NOT how (or by whom) it’s built Above the abstraction line

UC Berkeley “The Beauty and Joy of Computing” : Welcome, Abstraction (19) Garcia What is NOT a great example of abstraction in life?  Your permanent alumni address.  Your mobile phone number.  Your home address.  Your social security number. Consider this…

UC Berkeley “The Beauty and Joy of Computing” : Welcome, Abstraction (20) Garcia  Abstraction is one of the big ideas of computing and computational thinking  Remove detail or simplify  Generalize a solution Summary